Do not crash on gff3 empty line

src/jflow/featureiolib/gff3.py

@@ -173,6 +173,8 @@ class GFF3IO:
             self._line += 1
             if line.startswith('#') :
                 continue
+            if line == "" :
+                continue
             try:
                 gff_record = GFF3Record.fromGff(line)
             except: